This invention relates to an apparatus and method for relaying data from a database to a remote computer. More particularly, the invention relates to a system which is able to identify a specific remote computer for which predetermined data is available, and thereafter cause the data to be communicated from the database to that computer. Such systems typically employ a host computer at the database for managing the collection of information of varying interest to locations served by the different remote computers. In order to perform this function the host computer must assign subject matter descriptors to each newly collected file of information and identify the interested subscribers by comparing the assigned descriptors against interest profiles for each of the remote locations. Then the host computer must cause the opening of communication links with remote computers serving the identified subscribers and control the transmission of the information over those links.
An example of an application in which the present invention finds utility is an electronic subscription service which collects vast amounts of newly generated information for dissemination to a large number of subscribers. Heretofore such services have been available primarily only to remote systems of a dedicated type. Typically the subscriber has leased a specially configured electronic storage device equipped with a suitable modem for telephone communications with the host computer. When the host computer has concluded that newly received data fits the interest profile of a particular remote location, it has simply called the dedicated system at that location, established a telephone link and transmitted the data. For its part the local system has simply answered the call from the host, received the information and printed it, either contemporaneously or off line. While such a system effectively relays the desired information, the requirement for dedicated local hardware leads to inefficiencies in cost. The only available alternative has been an electronic mailbox or bulletin board arrangement wherein the remote computer has made periodic calls to the host to check on the contents of its "box".
The mailbox arrangement works reasonably well for persons who are regular users of computers, but it does not meet the requirements of a business person who has a need to monitor information of a specific type. For instance, a particular subscriber may want all reports regarding the business operations of a specific competitor and all reports of business acquisitions within a given industry. This could generate several reports a day for that one subscriber, and any particular report could be of overlapping interest to a number of other subscribers. A service of this type requires a huge database and encounters a variety of complex problems in targeting and delivering its reports. An example of such a service is one offered by Mead Data Central, Inc. under its service mark ECLIPS.
The recent wide proliferation of personal computers has greatly expanded the potential market for electronic subscription services. But the problems inherent host-initiated communications have discouraged market development. A call which is initiated by a host computer cannot be received unless the remote computer is turned on, is fully operational and is not otherwise engaged. Owners of personal computers are disposed to change their hardware, software or telephone numbers thereby thwarting incoming calls. Furthermore, a personal computer which can be reached by an electronic subscription service is vulnerable to calls from unauthorized sources. The resulting security problem has remained a serious obstacle to the marketing of electronic subscription services.